1. Field of the Invention
The present invention relates to barrier envelopes which are used to enclose and protect reusable photo-stimulable phosphor imaging plates, such plates being particularly used in the dental operatory with digital dental imaging systems.
2. Description of the Prior Art
Modern digital dental imaging systems utilize reusable photostimulable phosphor (PSP) imaging plates as opposed to the traditional x-ray film. The photostimulable phosphor imaging plate is enclosed within a barrier envelope and then positioned within the patient's oral cavity where it is then exposed. It is then removed from the oral cavity and from the barrier envelope and positioned in a light proof chamber for transport to a scanner where the imaging plate is inserted and digitally read, the imaging results being stored on a central processing unit.
The patient needs to be protected against cross contamination since the imaging plate is reusable, and must also be protected from the toxicity of the imaging plate. Still further, the imaging plate needs to be protected from the saliva and other substances found in the patient's mouth, and the exposed x-ray imaging plate needs to be protected from light until it is scanned or read. The existing envelopes currently used in the art are basically a rectangular envelop sized to accommodate various sizes of reusable photo-stimulable phosphor imaging plates common to the dental arts (sizes 0 to 4). The rectangular envelope has a seal peel-strip across the short dimension of its rectangular shape. The imaging plates are inserted lengthwise into the envelopes and sealed into the envelope after the removal of the peel-strip across one of the short dimensions. After sealing, the sealed end consists of two layers of the envelope flaps and the double sided adhesive strip. This flap is also formed with a “V” notch in its center to arguably facilitate the tearing of the envelope in the lengthwise direction when removing the imaging plate from the envelope. The lengthwise direction facilitates the ejection of the imaging plate.
The “V” notch may have a finite radius at its point due to the way the tooling is constructed, or due to wear of the tooling in the manufacture of the envelope. The presence of this finite radius decreases the ease with which the user can initiate a tear of the envelope. Still further, many of the barrier envelopes used with respect to imaging plates are constructed of plastic and typically have a grain in one direction, making it easier to tear in one direction, as opposed to another. Existing envelopes as constructed, are available only with the grain in the direction orthogonal to the direction of the tear as defined by the location of the tear notch and therefore contribute to making the tear more difficult than necessary. As the difficulty in tearing increases, it makes ejection of the imaging medium less controlled and more care must be exercised to aim the ejected medium, i.e. imaging plate, into its receiving receptacle. When the imaging medium is a photo-stimulable phosphor imaging plate, one side of the barrier envelope was provided with a transparent plastic material, and the other side is made of a light shielding material. In the existing technology, dark blue or navy blue are the colors used to shield the light from the imaging side of the imaging plate.
Applicant's barrier envelope construction addresses the short comings of the prior art and provides for a barrier envelope of improved design and easier opening.